1. Field of Invention
The present invention relates to a liquid crystal display device, an image signal correction circuit, an image signal correction method, and electronic devices designed to reduce, minimize or prevent deterioration of display quality caused by vertical cross-talk without using pre-charging.
2. Description of Related Art
In general, a liquid crystal panel is arranged to have liquid crystal sandwiched between a pair of substrates. These liquid crystal panels can be classified into various types, depending on the driving method. For example, an active-matrix-type panel, in which pixel electrodes are driven by three-terminal-type switching elements, is arranged as shown in FIG. 9.
Specifically, a liquid crystal panel of this type is arranged such that a plurality of scanning lines 112 extending in the row (X) direction, and a plurality of data lines 114 extending in the column (Y) direction, cross each other, and a pixel formed of a pair of a thin film transistor (hereinafter referred to as “TFT”) 116, which is an example of a three-terminal switching element, and a liquid crystal capacitor 105, is disposed corresponding to each of the intersections. Here, the liquid crystal capacitor 105 is formed by sandwiching liquid crystal between a rectangular pixel electrode and a counter electrode. In this regard, for the convenience of explanation, pixels are assumed to be arranged in a matrix state with m rows and n columns (wherein m and n are both integers).
Further, a peripheral circuit 120 is disposed so as to surround the area in which these pixels are disposed (display area). In detail, the peripheral circuit 120 includes a scanning line driving circuit 130, which turns scanning signals G1, G2, G3, . . . , Gm, supplied to each of the scanning lines 112, to an active level (H level) exclusively in sequence for each single horizontal scanning period, a data line driving circuit 140, which outputs sampling signals S1, S2, S3, . . . , Sn becoming an active level exclusively in sequence within each single horizontal scanning period, and a sampling circuit 150 formed of switches 151 for each data line 114. Among these elements, each of the switches 151 of the sampling circuit 150 turn on when the corresponding signals of the sampling control signals S1, S2, S3, . . . , Sn reach the active level, and samples an image signal VID supplied to an image signal line 171 to be supplied to the data lines 114.
Here, TFT 116, which is arranged at the intersection of a scanning line 112 and a data line 114, turns on when the scanning signal applied to the corresponding scanning line reaches the active level, and supplies the image signal VID, which is sampled on the corresponding data line, to the pixel electrode. At the same time, the counter electrode, corresponding to the pixel electrode, is shared with each liquid crystal capacitor 105, and maintained at a constant voltage over time. Thus, the voltage difference of the voltage of the counter electrode and the voltage of the image signal is applied across the liquid crystal capacitor 105. Subsequently, when TFT 116 turns off, the voltage applied to the liquid crystal capacitor is maintained by itself and the storage capacitor 119 connected in parallel.
At the same time, on each opposing face of both substrates, an orientation film that is processed by rubbing is disposed in such a manner that the longitudinal directions of molecules are twisted by about 90 degrees between both of the substrates, whereas a light polarizer, which depends on each orientation direction, is disposed on each back side of both substrates.
At this time, the light passing through the liquid crystal capacitor 105 optically rotates about 90 degrees along with the twisting of the liquid crystal molecules when the voltage applied to the capacitor is zero, whereas the higher the voltage becomes, the greater the molecules lean to the orientation of the electric field, thereby losing optical rotating power. Accordingly, for example, in the transmissive type, in the case where polarizers, having their polarizing axes orthogonal to each other in accordance with the orientation, are disposed on the incident side and rear side (in the case of normally white mode), if the voltage difference applied to both of the electrodes is zero, the light transmits to become a white display (transmittance ratio becomes high), whereas the greater the voltage difference applied to both of the electrodes, the stronger the light is dimmed, and finally becomes a black display (transmittance ratio becomes low). Consequently, by controlling the effective voltage applied to the liquid crystal capacitor 105 for each pixel, it is possible to display a predetermined gray level.